A senior Iraqi military officer predicts government forces will dislodge Islamic State militants from the western Iraqi city of Ramadi within days.

"In the coming days [there will be] good news [about] the complete liberation of Ramadi," Iraqia TV cited Army Chief of Staff Lieutenant Othman al-Ghanemi as saying on December 23.

Iraq's armed forces began advancing on December 22 on the last district held by the militants in the center of Ramadi, a Sunni city on the Euphrates river some 100 kilometers west of Baghdad that they captured in May.

If Ramadi is captured, it will be the second major city after Tikrit to be retaken from Islamic State in Iraq.

Progress has been slow because the government wants to rely entirely on its own troops and not use Shi'ite militias in order to avoid rights abuses such as occurred after the recapture of the city of Tikrit from the militants in April.